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• Log - Server kernel: INFO: task httpd:000000 blocked for more than 120 seconds

  - by valter

  Almost everyday my server is crashing due to hight server load, and even restarting apache or mysql can't solve the problem. I need to reboot the server to solve, or it crash again due to the high load. The log system records something like this when it crashes: Aug 11 18:33:53 server kernel: INFO: task httpd:20008 blocked for more than 120 seconds. Aug 11 18:33:53 server kernel: "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. Aug 11 18:33:53 server kernel: httpd D ffffffff801538ac 0 20008 5816 20066 19809 (NOTLB) Aug 11 18:33:53 server kernel: ffff81025a299dc8 0000000000000082 ffff81033b4c0740 ffffffff80009a14 Aug 11 18:33:53 server kernel: ffff8101063f8d80 0000000000000009 ffff8100b758f7e0 ffff8101c57187e0 Aug 11 18:33:53 server kernel: 00009436d4100b6c 000000000001d50f ffff8100b758f9c8 000000083b531588 Aug 11 18:33:53 server kernel: Call Trace: Aug 11 18:33:53 server kernel: [<ffffffff80009a14>] __link_path_walk+0x173/0xfb9 Aug 11 18:33:53 server kernel: [<ffffffff8002cc16>] mntput_no_expire+0x19/0x89 Aug 11 18:33:53 server kernel: [<ffffffff80063c4f>] __mutex_lock_slowpath+0x60/0x9b Aug 11 18:33:53 server kernel: [<ffffffff80023908>] __path_lookup_intent_open+0x56/0x97 Aug 11 18:33:53 server kernel: [<ffffffff80063c99>] .text.lock.mutex+0xf/0x14 Aug 11 18:33:53 server kernel: [<ffffffff8001b21f>] open_namei+0xea/0x712 Aug 11 18:33:54 server kernel: [<ffffffff8002768a>] do_filp_open+0x1c/0x38 Aug 11 18:33:54 server kernel: Firewall: *UDP_IN Blocked* IN=eth1 OUT= MAC=ff:ff:ff:ff:ff:ff:00:30:48:9e:6e:99:08:00 SRC=208.43.135.158 DST=255.255.255.255 LEN=151 TOS=0x00 PREC=0x00 TTL=64 ID=0 DF PROTO=UDP SPT=38354 DPT=6112 LEN=131 Aug 11 18:33:54 server kernel: [<ffffffff8001a061>] do_sys_open+0x44/0xbe Aug 11 18:33:54 server kernel: [<ffffffff8005d28d>] tracesys+0xd5/0xe0 I googled a lot trying to find a solution. But it looks that the solution is just to update the kernel or disk driver, thinks that I don't know how to do. In this url http://bugs.centos.org/view.php?id=4515 a lot o people report similar problems, except the fact that they are not related to httpd like mine. According to one member, one solution would be to add "elevator=noop " to /etc/grub.conf like in this example: title CentOS (2.6.18-238.12.1.el5xen) root (hd0,0) kernel /vmlinuz-2.6.18-238.12.1.el5xen ro root=/dev/VolGroup00/LogVol00 elevator=noop initrd /initrd-2.6.18-238.12.1.el5xen.img Would this really solve the problem? My disk are working in RAID. Can this cause some problem to my server? Is there any other solution?

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• Sysadmin 101: How can I figure out why my server crashes and monitor performance?

  - by bflora

  I have a Drupal-powered site that seems to have neverending performance problems. It was butt-slow about 5 months ago. I brought in some guys who installed nginx for anonymous visitors, ajaxified a few queries so they wouldn't fire during page load, and helped me find a few bottlenecks in the code. For about a month, the site was significantly faster, though not "fast" by any stretch of the word. Meanwhile, I'm now shelling out $400/month to Slicehost to host a site that gets less than 5,000/uniques a day. Yes, you read that right. Go Drupal. Recently the site started crashing again and is slow again. I can't afford to hire people to come in, study my code from top to bottom, and make changes that may or may not help anymore. And I can't afford to throw more hardware at the problem. So I need to figure out what the problem is myself. Questions: When apache crashes, is it possible to find out what caused it to crash? There has to be a way, right? If so, how can I do this? Is there software I can use that will tell me which process caused my server to die? (e.g. "Apache crashed because someone visited page X." or "Apache crashed because you were importing too many RSS items from feed X.") There's got to be a way to learn this, right? What's a good, noob-friendly way to monitor my current apache performance? My developer friends tell me to "just use Top, dude," but Top shows me a bunch of numbers without any context. I have no clue what qualifies as a bad number or a good number in Top, or which processes are relevant and which aren't. Are there any noob-friendly server monitoring tools out there? Ideally, I could have a page that would give me a color-coded indicator about how apache is performing and then show me a list of processes or pages that are sucking right now. This way, I could know when performance is bad and then what's causing it to be so bad. Why does PHP memory matter? My apparently has a 30MB memory foot print. Will it run faster if I bring that number down? Thanks for any advice. I spent a year or so trying to boost my advertising income so I could hire a contractor to solve my performance woes. I didn't want to have to learn all this sysadmin voodoo. I'm now resigned to the fact that might not have a choice.

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• What PHP, Xdebug and Eclipse configurations work on Windows 7 64 bit?

  - by thaddeusmt

  I have been mucking around for days, trying to find the right combination that lets me debug with breakpoints and variable viewing, in Eclipse, without crashing Apache. PHP 5.3? PHP 5.2? Eclipse Helios? Eclipse Galileo? One or the other with certain versions of xdebug or php? Or do I really need to use NetBeans or something else? Is my 64 bit OS the problem? Do need specific 64bit versions of PHP, Eclipse or Xdebug to work on Windows 7 64? Any special xdebug config options and tricks that I need in php.ini? Like turning off xdebug.profiler_enable or not using quotes around my zend_extension path to the xdebug dll? A Vhosts issue? Scrap the whole thing and go back to Win XP or Ubuntu? Here's what I've already been reading: http://stackoverflow.com/questions/4509245/so-eclipse-and-xdebug-walk-into-a-bar-and-then-my-apache-server-dies/4602473 http://stackoverflow.com/questions/206788/why-does-xdebug-crash-apache-on-every-xampp-install-ive-tried http://bugs.xdebug.org/view.php?id=459 https://bugs.eclipse.org/bugs/show_bug.cgi?id=312951#c8 http://stackoverflow.com/questions/2799936/xdebug-for-php-5-2-on-windows-7-64bit and so and so on... SO, xdebug bug tracker, eclipse bugzilla, etc, etc Basically what would be great is if folks could post their working (i.e. debugging with breakpoints and local variable viewing in Eclipse) Win7 64bit configurations, including: PHP version (5.3.1, 5.2.11, etc) Xdebug dll (2.1.0-5.3-vc6, etc) Xdebug php.ini config (zend_extension = "C:\xampp\php\ext\php_xdebug.dll", etc) Apache version (2.2.14, etc) Eclipse version Anything else important? The "secret ingredient"? Thanks! I miss my debugger since I got a new laptop with Win 7! Sadly it looks like some of the drivers (switchable graphics, multi-touch pad, etc) on my lappy don't work right with Ubuntu yet, so I feel a bit trapped on Win :( I know I will figure something out eventually, but I've been at this trial-and-error game a while and am seeking some guidance. (Originally posted on StackOverflow here, but moved to SuperUser:) http://stackoverflow.com/questions/4628215/what-php-xdebug-and-eclipse-configurations-work-on-windows-7-64-bit

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• Java: Reading a pdf file from URL into Byte array/ByteBuffer in an applet.

  - by Pol

  I'm trying to figure out why this particular snippet of code isn't working for me. I've got an applet which is supposed to read a .pdf and display it with a pdf-renderer library, but for some reason when I read in the .pdf files which sit on my server, they end up as being corrupt. I've tested it by writing the files back out again. I've tried viewing the applet in both IE and Firefox and the corrupt files occur. Funny thing is, when I trying viewing the applet in Safari (for Windows), the file is actually fine! I understand the JVM might be different, but I am still lost. I've compiled in Java 1.5. JVMs are 1.6. The snippet which reads the file is below. public static ByteBuffer getAsByteArray(URL url) throws IOException { ByteArrayOutputStream tmpOut = new ByteArrayOutputStream(); URLConnection connection = url.openConnection(); int contentLength = connection.getContentLength(); InputStream in = url.openStream(); byte[] buf = new byte[512]; int len; while (true) { len = in.read(buf); if (len == -1) { break; } tmpOut.write(buf, 0, len); } tmpOut.close(); ByteBuffer bb = ByteBuffer.wrap(tmpOut.toByteArray(), 0, tmpOut.size()); //Lines below used to test if file is corrupt //FileOutputStream fos = new FileOutputStream("C:\\abc.pdf"); //fos.write(tmpOut.toByteArray()); return bb; } I must be missing something, and I've been banging my head trying to figure it out. Any help is greatly appreciated. Thanks. Edit: To further clarify my situation, the difference in the file before I read then with the snippet and after, is that the ones I output after reading are significantly smaller than they originally are. When opening them, they are not recognized as .pdf files. There are no exceptions being thrown that I ignore, and I have tried flushing to no avail. This snippet works in Safari, meaning the files are read in it's entirety, with no difference in size, and can be opened with any .pdf reader. In IE and Firefox, the files always end up being corrupted, consistently the same smaller size. I monitored the len variable (when reading a 59kb file), hoping to see how many bytes get read in at each loop. In IE and Firefox, at 18kb, the in.read(buf) returns a -1 as if the file has ended. Safari does not do this. I'll keep at it, and I appreciate all the suggestions so far.

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• Spring/RMI server error

  - by 4herpsand7derpsago

  We have a Spring MVC web app (WAR) deploying to Tomcat (6.0.35) that launches a thread inside a separate JVM at deploy time (don't ask why - not my design) and then communicates with that thread via RMI over port 8888. Despite being totally convoluded, this was working perfectly fine up until yesterday, and now the thread is failing at startup and despite our best efforts to add logging into the mix, we are hitting a wall. This is the only exception we are able to find in the logs: Jun 12, 2012 3:11:36 AM com.ourapp.ImageController destroy SEVERE: Shutdown Error: Lookup of RMI stub failed; nested exception is java.rmi.ConnectException: Connection refused to host: localhost; nested exception is: java.net.ConnectException: Connection refused Jun 12, 2012 3:11:37 AM org.apache.catalina.core.StandardContext listenerStop SEVERE: Exception sending context destroyed event to listener instance of class org.springframework.web.context.ContextLoaderListener java.lang.NoClassDefFoundError: org/springframework/web/context/ContextCleanupListener at org.springframework.web.context.ContextLoaderListener.contextDestroyed(ContextLoaderListener.java:80) at org.apache.catalina.core.StandardContext.listenerStop(StandardContext.java:3973) at org.apache.catalina.core.StandardContext.stop(StandardContext.java:4577) at org.apache.catalina.startup.HostConfig.checkResources(HostConfig.java:1165) at org.apache.catalina.startup.HostConfig.check(HostConfig.java:1271) at org.apache.catalina.startup.HostConfig.lifecycleEvent(HostConfig.java:296) at org.apache.catalina.util.LifecycleSupport.fireLifecycleEvent(LifecycleSupport.java:119) at org.apache.catalina.core.ContainerBase.backgroundProcess(ContainerBase.java:1337) at org.apache.catalina.core.ContainerBase$ContainerBackgroundProcessor.processChildren(ContainerBase.java:1601) at org.apache.catalina.core.ContainerBase$ContainerBackgroundProcessor.processChildren(ContainerBase.java:1610) at org.apache.catalina.core.ContainerBase$ContainerBackgroundProcessor.run(ContainerBase.java:1590) at java.lang.Thread.run(Thread.java:662) Caused by: java.lang.ClassNotFoundException: org.springframework.web.context.ContextCleanupListener at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1387) at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1233) ... 12 more The ImageController is the Spring MVC Controller that is responsible for kicking off this daemon/spawned RMI thread. Based on the verbage of this error, does anybody have any idea what might be causing this "connection refused" error? Running a netstat -an | grep 8888 (this is a Linux machine) produces no output which means nothing is listening on that port. Thanks in advance for any ideas/suggestions that lead to a fix. Edit: Here's another ConnectionException we're seeing: Caused by: java.net.ConnectException: Connection refused at java.net.PlainSocketImpl.socketConnect(Native Method) at java.net.PlainSocketImpl.doConnect(PlainSocketImpl.java:351) at java.net.PlainSocketImpl.connectToAddress(PlainSocketImpl.java:213) at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:200) at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:366) at java.net.Socket.connect(Socket.java:529) at java.net.Socket.connect(Socket.java:478) at java.net.Socket.<init>(Socket.java:375) at java.net.Socket.<init>(Socket.java:189) at sun.rmi.transport.proxy.RMIDirectSocketFactory.createSocket(RMIDirectSocketFactory.java:22) at sun.rmi.transport.proxy.RMIMasterSocketFactory.createSocket(RMIMasterSocketFactory.java:128) at sun.rmi.transport.tcp.TCPEndpoint.newSocket(TCPEndpoint.java:595) ... 74 more

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• Avoid read-write access to bad sectors on HDD to continue working on the HDD

  - by goldenmean

  I have a HP Pavilion dv6446 notebook. It had Windows Vista Home premium. After 4.5+ years of usage, just recently it started malfunctioning. While working fine, its screen goes white or sometimes some thin black lines horizontally. Laptop freezes. Hard reboot works. Again it works for some 2 hrs or so, same error. To diagnose I did run the Memory and Hard disk check which is present in the Bios Setup. Memory test passed. Hard disk test returned an error saying something like - "Replace the hard disk". Bad.. Some sectors or platters have gone bad on the disk. (I confirmed this later by further tests mentioned below) Then I tried installing a Ubuntu 11.10. It listed 3 partitions /dev/sda1, sda2, sda2. It again gave error and could not install grub loader on /dev/sda1. Bad sectors. Then redid the Ubuntu installation, this time asked to to install the Ubuntu on /dev/sda3. and kept /dev/sda1 for /home. Installed fine, and works fine as well. Due to unavailability of WiFi/ Ethernet driver for that adapters under Ubuntu( at least I could not configure them and get the networking working at all), I decided to go back to reinstall windows Vista. It did install fine. I did not have to format one data partition which has my data. I just formatted one partition which installed Windows So in effect HDD has not undergone a full format here. Worked ok for 1 day. But same white screen and freeze happened. Looks like while it is in use, it accesses the bad sectors for storing some data and that's when it bombs. I am inclined to think HDD has not failed fully or crashed but has developed bad sectors. Else if it was a HDD crash, it would have refused to boot at all let alone install on it. Questions: Is there any HDD test check under windows or any such tools windows/linux based ewhere which can identify the bad sectors of the HDD and 'lock/isolate' them from further read-write access of any kind. If not what are my options, if any to salvage this laptop HDD without replacing it. EDIT: Would the Disk Error checking tool under windows help in any way?

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• Scala actors: receive vs react

  - by jqno

  Let me first say that I have quite a lot of Java experience, but have only recently become interested in functional languages. Recently I've started looking at Scala, which seems like a very nice language. However, I've been reading about Scala's Actor framework in Programming in Scala, and there's one thing I don't understand. In chapter 30.4 it says that using react instead of receive makes it possible to re-use threads, which is good for performance, since threads are expensive in the JVM. Does this mean that, as long as I remember to call react instead of receive, I can start as many Actors as I like? Before discovering Scala, I've been playing with Erlang, and the author of Programming Erlang boasts about spawning over 200,000 processes without breaking a sweat. I'd hate to do that with Java threads. What kind of limits am I looking at in Scala as compared to Erlang (and Java)? Also, how does this thread re-use work in Scala? Let's assume, for simplicity, that I have only one thread. Will all the actors that I start run sequentially in this thread, or will some sort of task-switching take place? For example, if I start two actors that ping-pong messages to each other, will I risk deadlock if they're started in the same thread? According to Programming in Scala, writing actors to use react is more difficult than with receive. This sounds plausible, since react doesn't return. However, the book goes on to show how you can put a react inside a loop using Actor.loop. As a result, you get loop { react { ... } } which, to me, seems pretty similar to while (true) { receive { ... } } which is used earlier in the book. Still, the book says that "in practice, programs will need at least a few receive's". So what am I missing here? What can receive do that react cannot, besides return? And why do I care? Finally, coming to the core of what I don't understand: the book keeps mentioning how using react makes it possible to discard the call stack to re-use the thread. How does that work? Why is it necessary to discard the call stack? And why can the call stack be discarded when a function terminates by throwing an exception (react), but not when it terminates by returning (receive)? I have the impression that Programming in Scala has been glossing over some of the key issues here, which is a shame, because otherwise it's a truly excellent book.

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• what can cause a folder to become indestructible?

  - by JustJeff

  I have a directory that I want to delete, but windows (xp sp3) is giving me the run-around and the folder is now effectively indestructible. Attempts to open the folder, either via explorer or cmd.exe are met with 'd:/temp/foo Is Not Accessible. Access is denied'. Attempts to delete the folder result in 'Cannot delete foo: The directory is not empty' So I can't delete it because supposedly it's not empty, but windows won't let me in it for some reason, so I can't clean it out first. There's nothing in it of consequence, and basically I just want to delete it at this point. Thinking that some other process must have a lock on it, I used the SysInternals 'handles' and Process Explorer to look for open handles with the directory name. These turned up no matches. (The directory name is not actually 'foo', it is something more unique but 'foo' is easier to type here). I put the machine through a restart, and the problem persists. I did a search for the folder name with regedit, to see what other apps might be aware of it. No match. The properties dialog was mildly interesting. The Read-Only attribute is 'semi-checked', i.e., the grayish check mark you get when some parts are and some parts aren't. Naturally I immediately unchecked this, and tried to delete the folder. No go. Opening properties again reveals the gray check mark next to Read-Only has returned. All the stats, size, size on disk, files, folders, all these are zero. There do not appear to be any shares on the folder, so that's not it either. Finally, I tried opening the partition's properties, and running the Tools/Error Checking utility. This didn't turn up any problems either. Fwiw, this directory was created by [a popular gui zip tool] when I tried to unpack a tar-and-zipped archive created on another system with command line utils. The archive was definitely corrupt, but I've never seen such a file do anything worse than crash the zip app, and certainly never leave permanent glitches in the file system. So what else can possibly be going on to make this folder behave this way?

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• Compiling PHP with GD crashes with EXC_BREAKPOINT (SIGTRAP) on PPC Mac

  - by Ömer

  First of all, I should say that I have searched the whole Internet for this problem but I couldn't find any solution yet. I have a Mac mini PowerPC (PPC) and I run Apache webserver (httpd-2.2.22) with PHP (5.4.0) and I do all the configure & compilation jobs by myself. If configure with: './configure' '--prefix=/usr/local/php5' '--mandir=/usr/share/man' '--infodir=/usr/share/info' '--sysconfdir=/etc' '--with-config-file-path=/etc' '--with-zlib' '--with-zlib-dir=/usr' '--with-openssl=/usr' '--without-iconv' '--enable-exif' '--enable-ftp' '--enable-mbstring' '--enable-mbregex' '--enable-sockets' '--with-mysql=/usr/local/mysql' '--with-pdo-mysql=/usr/local/mysql' '--with-mysqli=/usr/local/mysql/bin/mysql_config' '--with-apxs2=/usr/local/apache2/bin/apxs' '--with-mcrypt' then the PHP works flawlessly. But if I add the GD module by adding these to the script above: '--with-gd' '--with-jpeg-dir=/usr/local/lib' '--with-freetype-dir=/usr/X11R6' '--with-png-dir=/usr/X11R6' '--with-xpm-dir=/usr/X11R6' the PHP gets configured and compiled without any errors but it causes EXC_BREAKPOINT (SIGTRAP) (see the Crash Reporter log below) when I request a page which calls PHP module. It's obvious that something related to the GD module is causing this, probably FreeType module because it's present in the log but it may not be definite of course. When the PHP crashes (or more accurately, httpd) the CPU goes 100% for 10 to 15 seconds until it recovers. I need to use the GD module and keep the Mac mini PowerPC. So, what should I do to solve this problem? Process: httpd [79852] Path: /usr/local/apache2/bin/httpd Identifier: httpd Version: ??? (???) Code Type: PPC (Native) Parent Process: httpd [79846] Date/Time: 2013-11-04 15:44:28.444 +0200 OS Version: Mac OS X 10.5.8 (9L31a) Report Version: 6 Anonymous UUID: 0178B7F8-2241-43F7-A651-9E7234D41A37 Exception Type: EXC_BREAKPOINT (SIGTRAP) Exception Codes: 0x0000000000000001, 0x0000000093c11e0c Crashed Thread: 0 Application Specific Information: *** single-threaded process forked *** Thread 0 Crashed: 0 com.apple.CoreFoundation 0x93c11e0c __CFRunLoopFindMode + 328 1 com.apple.CoreFoundation 0x93c13d88 CFRunLoopAddSource + 276 2 com.apple.DiskArbitration 0x901a6e8c DAApprovalSessionScheduleWithRunLoop + 52 3 ...ple.CoreServices.CarbonCore 0x9512e67c _FSGetDiskArbSession(__DASession**, __DAApprovalSession**) + 540 4 ...ple.CoreServices.CarbonCore 0x9512e420 CreateDiskArbDiskForMountPath(char const*) + 84 5 ...ple.CoreServices.CarbonCore 0x9512d2c8 FSCacheableClient_GetVolumeCachedInfo(char const*, statfs const*, CachedVolumeInfo*, __DADisk*, __DADisk**) + 280 6 ...ple.CoreServices.CarbonCore 0x9512cca4 MountVolume(char const*, statfs*, unsigned char, unsigned char, __DADisk*, short*) + 352 7 ...ple.CoreServices.CarbonCore 0x9512ca48 MountInitialVolumes() + 172 8 ...ple.CoreServices.CarbonCore 0x9512c4d4 INIT_FileManager() + 164 9 ...ple.CoreServices.CarbonCore 0x9512c390 GetRetainedVolFSVCBByVolumeID(unsigned long) + 48 10 ...ple.CoreServices.CarbonCore 0x9512adf4 PathGetObjectInfo(char const*, unsigned long, unsigned long, VolumeInfo**, unsigned long*, unsigned long*, char*, unsigned long*, unsigned char*) + 184 11 ...ple.CoreServices.CarbonCore 0x9512acc4 FSPathMakeRefInternal(unsigned char const*, unsigned long, unsigned long, FSRef*, unsigned char*) + 64 12 libfreetype.6.dylib 0x0070a0fc FT_New_Face_From_Resource + 56 13 libfreetype.6.dylib 0x0070a3b0 FT_New_Face + 48 14 libphp5.so 0x0118d1a8 fontFetch + 824 15 libphp5.so 0x0118edac php_gd_gdCacheGet + 220 16 libphp5.so 0x0118d6d8 php_gd_gdImageStringFTEx + 360 17 libphp5.so 0x011763c0 php_imagettftext_common + 1504 18 libphp5.so 0x01176494 zif_imagefttext + 20 19 libphp5.so 0x014b9c68 zend_do_fcall_common_helper_SPEC + 1048 20 libphp5.so 0x01452898 _ZEND_DO_FCALL_SPEC_CONST_HANDLER + 440 21 libphp5.so 0x014ba878 execute + 776 22 libphp5.so 0x013f190c zend_execute_scripts + 316 23 libphp5.so 0x013779f4 php_execute_script + 596 24 libphp5.so 0x014bbe64 php_handler + 1972 25 httpd 0x000020c0 ap_run_handler + 96 26 httpd 0x00006ae0 ap_invoke_handler + 224 27 httpd 0x000305c4 ap_process_request + 116 28 httpd 0x0002c768 ap_process_http_connection + 104 29 httpd 0x00012d30 ap_run_process_connection + 96 30 httpd 0x00012ecc ap_process_connection + 92 31 httpd 0x000373e4 child_main + 1220 32 httpd 0x000376a8 make_child + 296 33 httpd 0x000377e4 startup_children + 100 34 httpd 0x000387d4 ap_mpm_run + 3988 35 httpd 0x0000a320 main + 3280 36 httpd 0x000019c0 start + 64

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• log4j performance

  - by Bob

  Hi, I'm developing a web app, and I'd like to log some information to help me improve and observe the app. (I'm using Tomcat6) First I thought I would use StringBuilders, append the logs to them and a task would persist them into the database like every 2 minutes. Because I was worried about the out-of-the-box logging system's performance. Then I made some test. Especially with log4j. Here is my code: Main.java public static void main(String[] args) { Thread[] threads = new Thread[LoggerThread.threadsNumber]; for(int i = 0; i < LoggerThread.threadsNumber; ++i){ threads[i] = new Thread(new LoggerThread("name - " + i)); } LoggerThread.startTimestamp = System.currentTimeMillis(); for(int i = 0; i < LoggerThread.threadsNumber; ++i){ threads[i].start(); } LoggerThread.java public class LoggerThread implements Runnable{ public static int threadsNumber = 10; public static long startTimestamp; private static int counter = 0; private String name; public LoggerThread(String name) { this.name = name; } private Logger log = Logger.getLogger(this.getClass()); @Override public void run() { for(int i=0; i<10000; ++i){ log.info(name + ": " + i); if(i == 9999){ int c = increaseCounter(); if(c == threadsNumber){ System.out.println("Elapsed time: " + (System.currentTimeMillis() - startTimestamp)); } } } } private synchronized int increaseCounter(){ return ++counter; } } } log4j.properties log4j.logger.main.LoggerThread=debug, f log4j.appender.f=org.apache.log4j.RollingFileAppender log4j.appender.f.layout=org.apache.log4j.PatternLayout log4j.appender.f.layout.ConversionPattern=%d{ABSOLUTE} %5p %c{1}:%L - %m%n log4j.appender.f.File=c:/logs/logging.log log4j.appender.f.MaxFileSize=15000KB log4j.appender.f.MaxBackupIndex=50 I think this is a very common configuration for log4j. First I used log4j 1.2.14 then I realized there was a newer version, so I switched to 1.2.16 Here are the figures (all in millisec) LoggerThread.threadsNumber = 10 1.2.14: 4235, 4267, 4328, 4282 1.2.16: 2780, 2781, 2797, 2781 LoggerThread.threadsNumber = 100 1.2.14: 41312, 41014, 42251 1.2.16: 25606, 25729, 25922 I think this is very fast. Don't forget that: in every cycle the run method not just log into the file, it has to concatenate strings (name + ": " + i), and check an if test (i == 9999). When threadsNumber is 10, there are 100.000 loggings and if tests and concatenations. When it is 100, there are 1.000.000 loggings and if tests and concatenations. (I've read somewhere JVM uses StringBuilder's append for concatenation, not simple concatenation). Did I missed something? Am I doing something wrong? Did I forget any factor that could decrease the performance? If these figures are correct I think, I don't have to worry about log4j's performance even if I heavily log, do I?

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• Java WebStart: <property ...> ignored when using <extension>?

  - by Thorbjørn Ravn Andersen

  I have a problem modernizing a Java WebStart application under Java 6 u 13 (the latest at this moment) We desire to use the new mechanism to have several master configuration files each with their own configuration , which then "include" another jnlp file which is autogenerated to ensure that the jar list is accurate. After quite a bit of poking I have made it work, except for the fact that the properties defined in the master file is not available to the program when Main is invoked. The master JNLP looks like (anonymized): <jnlp> <information> <title>...</title> <vendor>...</vendor> <description>...</description> <description kind="short">...</description> <homepage href="http://....jnlp"/> <icon href="http://....gif"/> <!-- <offline-allowed/> --> </information> <security> <all-permissions/> </security> <resources> <j2se version="1.6+"/> <extension href="http://...extension.jnlp" /> <property name="server.name" value="SERVER"/> </resources> <application-desc main-class="Main"/> </jnlp> and the extension.jnlp looks like: <!-- Generated automatically. Do not edit! --> <jnlp> <information> <title>extension built 2009-04-22 12:39:58 CEST</title> <vendor>...</vendor> </information> <security><all-permissions/></security> <resources> <jar href="A.jar" /> <jar href="B.jar" /> <jar href="logback-classic-0.9.14.jar" /> <jar href="logback-core-0.9.14.jar" /> <jar href="slf4j-api-1.5.6.jar" /> </resources> <component-desc /> </jnlp> I have tried putting the proprty in the extension.jnlp too. Did not help. The JVM is reused and not relaunched according to the log in the Java Plugin Console. Any suggestions?

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• What's the best Scala build system?

  - by gatoatigrado

  I've seen questions about IDE's here -- Which is the best IDE for Scala development? and What is the current state of tooling for Scala?, but I've had mixed experiences with IDEs. Right now, I'm using the Eclipse IDE with the automatic workspace refresh option, and KDE 4's Kate as my text editor. Here are some of the problems I'd like to solve: use my own editor IDEs are really geared at everyone using their components. I like Kate better, but the refresh system is very annoying (it doesn't use inotify, rather, maybe a 10s polling interval). The reason I don't use the built-in text editor is because broken auto-complete functionalities cause the IDE to hang for maybe 10s. rebuild only modified files The Eclipse build system is broken. It doesn't know when to rebuild classes. I find myself almost half of the time going to project-clean. Worse, it seems even after it has finished building my project, a few minutes later it will pop up with some bizarre error (edit - these errors appear to be things that were previously solved with a project clean, but then come back up...). Finally, setting "Preferences / Continue launch if project contains errors" to "prompt" seems to have no effect for Scala projects (i.e. it always launches even if there are errors). build customization I can use the "nightly" release, but I'll want to modify and use my own Scala builds, not the compiler that's built into the IDE's plugin. It would also be nice to pass [e.g.] -Xprint:jvm to the compiler (to print out lowered code). fast compiling Though Eclipse doesn't always build right, it does seem snappy -- even more so than fsc. I looked at Ant and Maven, though haven't employed either yet (I'll also need to spend time solving #3 and #4). I wanted to see if anyone has other suggestions before I spend time getting a suboptimal build system working. Thanks in advance! UPDATE - I'm now using Maven, passing a project as a compiler plugin to it. It seems fast enough; I'm not sure what kind of jar caching Maven does. A current repository for Scala 2.8.0 is available [link]. The archetypes are very cool, and cross-platform support seems very good. However, about compile issues, I'm not sure if fsc is actually fixed, or my project is stable enough (e.g. class names aren't changing) -- running it manually doesn't bother me as much. If you'd like to see an example, feel free to browse the pom.xml files I'm using [github]. UPDATE 2 - from benchmarks I've seen, Daniel Spiewak is right that buildr's faster than Maven (and, if one is doing incremental changes, Maven's 10 second latency gets annoying), so if one can craft a compatible build file, then it's probably worth it...

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• Apache server completely freezes until it gets restarted

  - by nbv4

  My server does this every few days. What sucks is that it always seems to do this right after I go to bed, so when I wake up, I'm greeted with the fact that my server has been down for the past 6 or 7 hours. When I first noticed this, I added a cronjob that tries to restart the server every 15 minutes, but I guess that didn't fix it. Once I noticed the server was down, I can this command: /etc/init.d/apache2 restart * Restarting web server apache2 apache2: Could not reliably determine the server's fully qualified domain name, using 127.0.0.1 for ServerName ... waiting ...........................................................apache2: Could not reliably determine the server's fully qualified domain name, using 127.0.0.1 for ServerName httpd (pid 17597) already running ...which is odd, because a restart should restart the server, even if it's already running, correct? I eventually had to "stop" then "start" to get it working again. I then looked through the logs, and found something very weird. It seems that around the time the server crashed, the logs have entries that are wildly out of order. It looks a little like this: xx.xxx.xxx.x - - [21/Apr/2010:06:32:05 -0400] "GET / blah" xx.xxx.xxx.x - - [21/Apr/2010:06:51:25 -0400] "GET / blah" x.xx.xxx.xxx - - [21/Apr/2010:06:38:23 -0400] "GET / blah" xxx.xx.xx.xx - - [21/Apr/2010:06:31:56 -0400] "GET / blah" xxx.xx.xx.xx - - [21/Apr/2010:06:51:49 -0400] "GET / blah" xx.xx.xxx.xx - - [21/Apr/2010:06:33:20 -0400] "GET / blah" I don't think the problem is memory, because this: tells me that right before the crash, memory usage is fine. I'm running apache with the worker mpm, here are the settings for that: <IfModule mpm_worker_module> StartServers 1 MaxClients 100 MinSpareThreads 5 MaxSpareThreads 10 ThreadsPerChild 10 MaxRequestsPerChild 3000 </IfModule> This apache server is running a bunch of stuff, but most of the traffic comes from a django project I'm hosting, that uses mod_wsgi. There also is a simple machines forum that is running off of mod_fcgid. Those setting are below: <IfModule mod_fcgid.c> MaxRequestsPerProcess 500 MaxProcessCount 3 AddHandler fcgid-script .php .fcgi AddHandler cgi-script .cgi .pl FCGIWrapper "/usr/bin/php-cgi" .php </IfModule> Anyone know of anything else I can check? I've just about tweaked every single setting I can think of, yet these freezes still happen.

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• amd gpu but display on intel integrated graphics

  - by pitseeker

  On my Ubuntu 12.04 I connected my monitor to the onboard intel graphics. I'd like to use my ati radeon 6770 for opencl tasks (e.g. bitcoin mining). So far I couldn't figure out how to get the ati driver working. When calling "aticonfig --initial -f" it always writes a new xorg.conf that ignores the intel graphics. At boot time it works only when I attached the monitor to the ati card. So I manually tampered with the xorg.conf and got this: Section "ServerLayout" Identifier "Default Monitor" Screen 0 "myscreen" 0 0 Screen 1 "deadscreen" RightOf "myscreen" EndSection Section "Module" EndSection Section "Monitor" Identifier "Default Monitor" Option "VendorName" "Monitor Vendor" Option "ModelName" "Monitor Name" Option "DPMS" "true" EndSection Section "Monitor" Identifier "null Monitor" Option "Enable" "false" EndSection Section "Device" Identifier "Intel Integrated Graphics" Driver "intel" BusID "PCI:0:2:0" Screen 0 EndSection Section "Device" Identifier "aticonfig-Device[0]-0" Driver "fglrx" BusID "PCI:1:0:0" Screen 1 EndSection Section "Screen" Identifier "myscreen" Device "Intel Integrated Graphics" Monitor "Default Monitor" DefaultDepth 24 SubSection "Display" Viewport 0 0 Depth 24 EndSubSection EndSection Section "Screen" Identifier "deadscreen" Device "aticonfig-Device[0]-0" Monitor "null Monitor" DefaultDepth 24 SubSection "Display" Viewport 0 0 Depth 24 EndSubSection EndSection I think this might be the right way since I see that X tries to start both drivers in /var/log/Xorg.0.log. However the fglrx driver seems crash (end of xorg.0.log): Backtrace: [ 6.625] 0: /usr/bin/X (xorg_backtrace+0x26) [0x7fb5cd41b846] [ 6.625] 1: /usr/bin/X (0x7fb5cd293000+0x18c6ea) [0x7fb5cd41f6ea] [ 6.625] 2: /lib/x86_64-linux-gnu/libpthread.so.0 (0x7fb5cc5b9000+0xfcb0) [0x7fb5cc5c8cb0] [ 6.625] 3: /usr/lib/x86_64-linux-gnu/xorg/extra-modules/extra-modules.dpkg-tmp/modules/drivers/fglrx_drv.so (xdl_xs111_atiddxGetGPUMapInfo+0x1b1) [0x7fb5c88e16b1] [ 6.625] 4: /usr/lib/x86_64-linux-gnu/xorg/extra-modules/extra-modules.dpkg-tmp/modules/drivers/fglrx_drv.so (atiddxGetGPUMapInfo+0xd) [0x7fb5c87bcc0d] [ 6.625] 5: /usr/lib/x86_64-linux-gnu/xorg/extra-modules/extra-modules.dpkg-tmp/modules/extensions/libglx.so (0x7fb5ca12d000+0x1ab29) [0x7fb5ca147b29] [ 6.625] 6: /usr/lib/x86_64-linux-gnu/xorg/extra-modules/extra-modules.dpkg-tmp/modules/extensions/libglx.so (0x7fb5ca12d000+0x1cf8c) [0x7fb5ca149f8c] [ 6.625] 7: /usr/lib/x86_64-linux-gnu/xorg/extra-modules/extra-modules.dpkg-tmp/modules/extensions/libglx.so (0x7fb5ca12d000+0x1ee55) [0x7fb5ca14be55] [ 6.626] 8: /usr/bin/X (InitExtensions+0x99) [0x7fb5cd350069] [ 6.626] 9: /usr/bin/X (0x7fb5cd293000+0x3d605) [0x7fb5cd2d0605] [ 6.626] 10: /lib/x86_64-linux-gnu/libc.so.6 (__libc_start_main+0xed) [0x7fb5cb44e76d] [ 6.626] 11: /usr/bin/X (0x7fb5cd293000+0x3daad) [0x7fb5cd2d0aad] [ 6.626] Segmentation fault at address 0x14 [ 6.626] Caught signal 11 (Segmentation fault). Server aborting [ 6.626] I'd be very happy if someone can give me a hint on how to configure my ATI card while using the integrated graphics for display. Update I used most of jjhughes57 config and successfully booted the X server on intel (keyboard layout is changed though, funnily). Unfortunately the 2nd X server (fglrx) doesn't fully start. It shuts itself down right after starting [ 6.265] (II) fglrx(0): Restoring Recent Mode via PCS is not supported in RANDR 1.2 capable environments [ 6.296] (II) UnloadModule: "mouse" [ 6.296] (II) Unloading mouse [ 6.296] (II) UnloadModule: "kbd" [ 6.296] (II) Unloading kbd [ 6.298] (II) fglrx(0): Shutdown CMMQS [ 6.298] (II) fglrx(0): [uki] removed 1 reserved context for kernel [ 6.298] (II) fglrx(0): [uki] unmapping 8192 bytes of SAREA 0x2000 at 0x7fbef8209000 [ 6.337] (II) fglrx(0): Interrupt handler Shutdown. [ 6.470] ddxSigGiveUp: Closing log [ 6.470] Server terminated successfully (0). Closing log file. Thanks for any hints what is wrong here.

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• Is it safe to enable forced ASLR via EMET on Windows?

  - by D.W.

  I'd like to enable forced ASLR for all DLLs on Windows. Is this safe? Background: ASLR is an important security mechanism that helps defend against code injection attacks. DLLs can opt into ASLR, and most do, but some DLLs have not opted into ASLR. If a program loads even a single non-ASLRized DLL, then the program doesn't get the benefit/protection of ASLR. This is a problem, because there are a non-trivial number of DLLs that haven't opted into ASLR. For instance, it was recently revealed that Dropbox injects a DLL into a bunch of processes, and the Dropbox DLL doesn't have ASLR turned on, which negates any ASLR protection they otherwise would have had. Unfortunately, there are many other widely used DLLs that haven't opted into ASLR. This is bad for system security. Microsoft provides several ways to turn on ASLR for all DLLs, even ones that haven't opted into ASLR: On Windows 7 and Windows Server 2008, you can enable "Force ASLR" in the registry. On all Windows versions, you can use Microsoft's EMET tool and enable EMET's "Mandatory ASLR" option. These methods are possible because all DLLs are compiled as position-independent code and they can be relocated to a random location even if they haven't opted into ASLR. These options will ensure that ASLR is turned on, even if the developers of the DLL forgot to opt into ASLR. Thus, forcing on ASLR systemwide may help system security. In principle, turning on forced ASLR could potentially break a poorly-written DLL, so there is some risk of breakage. I'm interested in finding out just significant this risk is. I have the suspicion that this kind of breakage might be extremely rare. Here's what I've been able to find: Microsoft has done compatibility testing with several dozen widely used applications. The only one they found where Mandatory ASLR causes problems is Windows Media Player. All the other applications continue working fine. (See pp.39-41 of this document.) I've seen some anecdotal reports that enabling "Mandatory ASLR"/"Force ASLR" is fine and unlikely to cause problems. CERT reports that AMD and ATI video drivers used to crash if you enabled forced ASLR, but their latest drivers have now fixed this problem. They don't show any other drivers with this problem. A forum post from Microsoft shows no other applications with compatibility problems if ASLR is forced on, as of 2011. A user reports that borderlands.exe, a video game by Gearbox Software, crashes if you turn on mandatory ASLR. What else should I know? Is it relatively safe to turn on Force ASLR / Mandatory ASLR systemwide to harden the secuity of my system, or will I be in for a world of pain and broken applications? How significant is the risk of compatibility problems and broken applications?

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• Real-time offline folder-to-folder backup application needed (Windows)

  - by niktech

  I recently started using Intel Matrix Storage RAID solution that allowed me to use my 5 1TB drives for two RAID volumes. First one a 1TB RAID 0 striped across all 5 drives and second one a RAID 5 across the rest of the free space on all drives (around 2.85TB usable space). The RAID 0 I use for OS, applications and games while the RAID 5 I use as a more-permanent type storage (photos, etc). Now I do realize that running the OS and applications on RAID 0 across 5 drives is very dangerous, which is what brings up the following question. Is there a reliable freeware realtime backup application that can backup a set of folders from one drive to another drive (no online backups needed)? I've already tried a few (Mozy, Yadis, Comodo Backup, GFI Backup, Idoo, Crash Plan) but none meet my requirements: Low CPU and RAM usage. Realtime Backups - as soon as a file is modified in the source folder, it is added to the backup queue which will be processed with the lowest priority when the CPU is idle. This backup queue should persist in cases of computer restarts (ie: the source and destination folders should always have the same set of files, except for the ones waiting in the backup queue). Incremental Backups - if only 10 bytes changed in a 1GB file, the app should only copy those 10 new bytes. Ability to back up locked and opened files (some apps, like Yadis, can't back up critical files like browser favorites). Ability to run as a service (no need for any user to log-in to have the app started). Optional requirements: Compression of the destination into a well-known format (RAR, Zip) that can be directly read without the use of the application. Preset source folders (such as Browser Favorites, Game Saves, Application Settings, etc). The idea is to use RAID 0 array as "semi-persistent RAM-like" storage which in case of a failure can be quickly rebuilt by reinstalling the OS, apps and games and copying over the settings, saves, favorites from the RAID 5. I'm also thinking of taking this RAID 0 as RAM idea to the extreme with SSDs (as soon as we get some nice 6Gb/s SATA III SSDs out there), where a couple of SSDs chained in RAID 0 will work as yet another semi-persistent cache layer sitting between the RAM and the HD. I'm just hoping there already exists an application that satisfies these requirements... otherwise I'll have to write one myself, which I would prefer not to do.

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• What does these FindBug messages show?

  - by Hans Klock

  Not every description from from http://findbugs.sourceforge.net/bugDescriptions.html is clear to me. Sure, I can study the implementation but if somebody is more experienced then me, some explanation and examples would be great. Do you have some examples for UI_INHERITANCE_UNSAFE_GETRESOURCE when this is getting a problem? In BX_UNBOXED_AND_COERCED_FOR_TERNARY_OPERATOR I don't see the problem either. If one type is "bigger" then the other, for example int and float, then the result is float. If its Integer and Float its the wrapper Float too. That's what I expect. Does the GC_UNRELATED_TYPES really help to find errors? Isn't it the job of the compiler to check, if--taking the given example--Foo can't go into a Collection<String>. Does HE_SIGNATURE_DECLARES_HASHING_OF_UNHASHABLE_CLASS mean something like bla(Foo f){hashtable.put(f);}, where ´Foo´ is not hashable? Does FingBugs "see" the subclasses too? NP_GUARANTEED_DEREF_ON_EXCEPTION_PATH is stronger "wrong" then NP_ALWAYS_NULL_EXCEPTION? Why two error cases and with NP_NULL_ON_SOME_PATH_EXCEPTION even one more? Sounds very similar to me. What is an example of SIO_SUPERFLUOUS_INSTANCEOF? Something like foo(String s){if (s intenceof String) .... This does a null check too, but this is not the test here... NN_NAKED_NOTIFY. I my opinion the description is not clear. A change of the state is not necessary. If I use new Object() to wait and notify on I don't change the object state. Or is state the lock-state? I don't get it. SP_SPIN_ON_FIELD. Can this really happen that a compiler will move this outside from a loop? This doesn't make sense to me because from outside a Thread can always change the values. And if the variable is volatile the JVM can't cache the value. So what's the meaning? That is the difference between STCAL_STATIC_CALENDAR_INSTANCE and STCAL_INVOKE_ON_STATIC_CALENDAR_INSTANCE or STCAL_INVOKE_ON_STATIC_DATE_FORMAT_INSTANCE/STCAL_STATIC_SIMPLE_DATE_FORMAT_INSTANCE? Why is XXXX.class in WL_USING_GETCLASS_RATHER_THAN_CLASS_LITERAL better then getClass()? A getClass() in a superclass called from the subclass will always return the Class object from the subclass which is good I think. What exactly does EQ_UNUSUAL do? It should check that the argument is of the same type of the class itself but it does't? Did you ever had problems with breaks? Is there real value with SF_SWITCH_FALLTHROUGH? Sounds to strong for me. No idea what TQ_EXPLICIT_UNKNOWN_SOURCE_VALUE_REACHES_ALWAYS_SINK and TQ_EXPLICIT_UNKNOWN_SOURCE_VALUE_REACHES_NEVER_SINK could be.

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• debian packages version convention

  - by JackWu

  I'm using debian/Ubuntu, and get confused about versions of packages. When using dpkg -l command, I get: ii vim 2:7.3.429-2ubuntu2.1 Vi IMproved - enhanced vi editor ii vim-common 2:7.3.429-2ubuntu2.1 Vi IMproved - Common files ii vim-runtime 2:7.3.429-2ubuntu2.1 Vi IMproved - Runtime files ii vim-tiny 2:7.3.429-2ubuntu2.1 Vi IMproved - enhanced vi editor - compact version ii virt-what 1.11-1 detect if we are running in a virtual machine ii w3m 0.5.3-5ubuntu1 WWW browsable pager with excellent tables/frames support ii watershed 6 reduce superfluous executions of idempotent command ii wget 1.13.4-2ubuntu1 retrieves files from the web ii whiptail 0.52.11-2ubuntu10 Displays user-friendly dialog boxes from shell scripts ii whoopsie 0.1.33 Ubuntu crash database submission daemon ii wimlib9 1.5.0-1~webupd8~precise Library to extract, create, modify, and mount WIM files ii wimtools 1.5.0-1~webupd8~precise Tools to extract, create, modify, and mount WIM files ii wireless-tools 30~pre9-5ubuntu2 Tools for manipulating Linux Wireless Extensions ii wpasupplicant 0.7.3-6ubuntu2.1 client support for WPA and WPA2 (IEEE 802.11i) ii x11-common 1:7.6+12ubuntu2 X Window System (X.Org) infrastructure ii x11-utils 7.6+4ubuntu0.1 X11 utilities ii xauth 1:1.0.6-1 X authentication utility ii xbitmaps 1.1.1-1 Base X bitmaps ii xclip 0.12-1 command line interface to X selections ii xfonts-encodings 1:1.0.4-1ubuntu1 Encodings for X.Org fonts ii xfonts-utils 1:7.6+1 X Window System font utility programs ii xkb-data 2.5-1ubuntu1.3 X Keyboard Extension (XKB) configuration data ii xml-core 0.13 XML infrastructure and XML catalog file support rc xpdf 3.02-21build1 Portable Document Format (PDF) reader ii xterm 271-1ubuntu2.1 X terminal emulator ii xz-lzma 5.1.1alpha+20110809-3 XZ-format compression utilities - compatibility commands ii xz-utils 5.1.1alpha+20110809-3 XZ-format compression utilities ii zabbix-agent 1:1.8.11-1 network monitoring solution - agent ii zlib1g 1:1.2.3.4.dfsg-3ubuntu4 compression library - runtime ii zlib1g-dev 1:1.2.3.4.dfsg-3ubuntu4 compression library - development ii zsh 4.3.17-1ubuntu1 shell with lots of features The third column is version, but it all messed up in a way I can't understand. I mean, different packages use total different naming specification. Here are the major questions: Why there are ubuntu in them, and there are not? what all the special -~+ mean? alpha and build, dfsg, what are they? Can I just use them casually? vim and other packages have 2:, what does that mean? How version comparison works, since they can be so different? Can anyone please explain this to me? Or where can I find an official document? Thanks in advance.

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• Java Runtime.freeMemory() returning bizarre results when adding more objects

  - by Sotirios Delimanolis

  For whatever reason, I wanted to see how many objects I could create and populate a LinkedList with. I used Runtime.getRuntime().freeMemory() to get the approximation of free memory in my JVM. I wrote this: public static void main(String[] arg) { Scanner kb = new Scanner(System.in); List<Long> mem = new LinkedList<Long>(); while (true) { System.out.println("Max memory: " + Runtime.getRuntime().maxMemory() + ". Available memory: " + Runtime.getRuntime().freeMemory() + " bytes. Press enter to use more."); String s = kb.nextLine(); if (s.equals("m")) for (int i = 0; i < 1000000; i++) { mem.add(new Long((new Random()).nextLong())); } } } If I write in m, the app adds a million Long objects to the list. You would think the more objects (to which we have references, so can't be gc'ed), the less free memory. Running the code: Max memory: 1897725952. Available memory: 127257696 bytes. m Max memory: 1897725952. Available memory: 108426520 bytes. m Max memory: 1897725952. Available memory: 139873296 bytes. m Max memory: 1897725952. Available memory: 210632232 bytes. m Max memory: 1897725952. Available memory: 137268792 bytes. m Max memory: 1897725952. Available memory: 239504784 bytes. m Max memory: 1897725952. Available memory: 169507792 bytes. m Max memory: 1897725952. Available memory: 259686128 bytes. m Max memory: 1897725952. Available memory: 189293488 bytes. m Max memory: 1897725952. Available memory: 387686544 bytes. The available memory fluctuates. How does this happen? Is the GC cleaning up other things (what other things are there on the heap to really clean up?), is the freeMemory() method returning an approximation that's way off? Am I missing something or am I crazy?

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• How to recover a MySQL InnoDB table?

  - by Kau-Boy

  When I try to launch the Plesk administration page of you server I get the following error: ERROR: PleskMainDBException MySQL query failed: MySQL server has gone away The MySQL Server is working well. Although it seems that the plesk database is somehow corrupt and any action on this database results in a restart of the mysql process, so even queries to other databases on the same MySQL server will be lost. If I try to connect to the plesk database using phpMyAdmin, I can only see the number of tables, the database had originally. But I am not able to open the tables listing. As soon as I try it, the mysql process crashes again. Trying to connect to the database using ssh works. I can even run a SELECT statement against any table an get a result. I don't know if it is an plesk error or an error of the psa database or even the MySQL server. Can you give me any tips on how to recover the plesk system. Should I try to repair the Plesk installation before. And if so, how can I do it and will all my settings get lost doing it? EDIT: Trying to dump the database, I get the following error: mysqldump: Got error: 2013: Lost connection to MySQL server during query when using LOCK TABLES EDIT: I could find out, that the table 'data_bases' is responsible for the crash of the MySQL server process. But trying to repair it using a REPAIR TABLE statement doesn't work. EDIT: I now dropped the whole database and restored it from a dump. But why I try to recover the data_bases table I get the following error: ERROR 1005 (HY000) at line 24: Can't create table './psa/data_bases.frm' (errno: 121) I am not able to create the table again. Somewhere in the MySQL system there is still some information about this table. I tested the same thing locally. If I just delete the table files and then try to create the table again I get the same error. If I drop the table through MySQL, I can create the table again afterwards. But trying to drop the table using MySQL the whole MySQL system crashed. Is there any way to solve that issue?

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• Zero code coverage with cobertura 1.9.2 but tests are working

  - by eraonel

  I run the code coverage target: <junit fork="yes" dir="${basedir}" failureProperty="test.failed"> <!-- Note the classpath order: instrumented classes are before the original (uninstrumented) classes. This is important. --> <classpath path="${instrumented.dir}" /> <classpath path="${classes.dir}" /> <classpath refid="classpath" /> <!-- The instrumented classes reference classes used by the Cobertura runtime, so Cobertura and its dependencies must be on your classpath. --> <classpath refid="cobertura.classpath" /> <formatter type="xml" /> <!--<test name="${testcase}" todir="${reports.xml.dir}" if="testcase" />--> <batchtest fork="yes" todir="${reports.xml.dir}"> <fileset dir="${classes.dir}"> <include name="**/generated/AllTests.class" /> </fileset> </batchtest> </junit> <junitreport todir="${reports.xml.dir}"> <fileset dir="${reports.xml.dir}"> <include name="TEST-*.xml" /> </fileset> <report format="frames" todir="${reports.html.dir}" /> </junitreport> Then I get the following output ( when using fork="true"): java.lang.reflect.InvocationTargetException at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) at java.lang.reflect.Method.invoke(Method.java:585) at net.sourceforge.cobertura.util.FileLocker.lock(FileLocker.java:124) at net.sourceforge.cobertura.coveragedata.ProjectData.saveGlobalProjectData(ProjectData.java:331) at net.sourceforge.cobertura.coveragedata.SaveTimer.run(SaveTimer.java:31) at java.lang.Thread.run(Thread.java:595) Caused by: java.io.IOException: No locks available at sun.nio.ch.FileChannelImpl.lock0(Native Method) at sun.nio.ch.FileChannelImpl.lock(FileChannelImpl.java:784) at java.nio.channels.FileChannel.lock(FileChannel.java:865) ... 8 more --------------------------------------- Unable to get lock on /vobs/rnc/rrt/roam2/roamSs/RoamMao_swb/RoamMao_bldu/ant_build/cobertura.ser.lock: null This is known to happen on Linux kernel 2.6.20. Make sure cobertura.jar is in the root classpath of the jvm process running the instrumented code. If the instrumented code is running in a web server, this means cobertura.jar should be in the web server's lib directory. Don't put multiple copies of cobertura.jar in different WEB-INF/lib directories. Only one classloader should load cobertura. It should be the root classloader. I am using Ant 1.7.0 and cobertura 1.9.2. Any ideas why there is no coverage? Test run ok as I see in my target. I have tried to switch java versions ( 1.5.0_06 and 1.6.0_10) but no difference.

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• Difference in DocumentBuilder.parse when using JRE 1.5 and JDK 1.6

  - by dhiller

  Recently at last we have switched our projects to Java 1.6. When executing the tests I found out that using 1.6 a SAXParseException is not thrown which has been thrown using 1.5. Below is my test code to demonstrate the problem. import java.io.StringReader; import javax.xml.parsers.DocumentBuilder; import javax.xml.parsers.DocumentBuilderFactory; import javax.xml.transform.stream.StreamSource; import javax.xml.validation.SchemaFactory; import org.junit.Test; import org.xml.sax.InputSource; import org.xml.sax.SAXParseException; /** * Test class to demonstrate the difference between JDK 1.5 to JDK 1.6. * * Seen on Linux: * * <pre> * #java version "1.6.0_18" * Java(TM) SE Runtime Environment (build 1.6.0_18-b07) * Java HotSpot(TM) Server VM (build 16.0-b13, mixed mode) * </pre> * * Seen on OSX: * * <pre> * java version "1.6.0_17" * Java(TM) SE Runtime Environment (build 1.6.0_17-b04-248-10M3025) * Java HotSpot(TM) 64-Bit Server VM (build 14.3-b01-101, mixed mode) * </pre> * * @author dhiller (creator) * @author $Author$ (last editor) * @version $Revision$ * @since 12.03.2010 11:32:31 */ public class TestXMLValidation { /** * Tests the schema validation of an XML against a simple schema. * * @throws Exception * Falls ein Fehler auftritt * @throws junit.framework.AssertionFailedError * Falls eine Unit-Test-Pruefung fehlschlaegt */ @Test(expected = SAXParseException.class) public void testValidate() throws Exception { final StreamSource schema = new StreamSource( new StringReader( "<?xml version=\"1.0\" encoding=\"UTF-8\"?>" + "<xs:schema xmlns:xs=\"http://www.w3.org/2001/XMLSchema\" " + "elementFormDefault=\"qualified\" xmlns:xsd=\"undefined\">" + "<xs:element name=\"Test\"/>" + "</xs:schema>" ) ); final String xml = "<Test42/>"; final DocumentBuilderFactory newFactory = DocumentBuilderFactory.newInstance(); newFactory.setSchema( SchemaFactory.newInstance( "http://www.w3.org/2001/XMLSchema" ).newSchema( schema ) ); final DocumentBuilder documentBuilder = newFactory.newDocumentBuilder(); documentBuilder.parse( new InputSource( new StringReader( xml ) ) ); } } When using a JVM 1.5 the test passes, on 1.6 it fails with "Expected exception SAXParseException". The Javadoc of the DocumentBuilderFactory.setSchema(Schema) Method says: When errors are found by the validator, the parser is responsible to report them to the user-specified ErrorHandler (or if the error handler is not set, ignore them or throw them), just like any other errors found by the parser itself. In other words, if the user-specified ErrorHandler is set, it must receive those errors, and if not, they must be treated according to the implementation specific default error handling rules. The Javadoc of the DocumentBuilder.parse(InputSource) method says: BTW: I tried setting an error handler via setErrorHandler, but there still is no exception. Now my question: What has changed to 1.6 that prevents the schema validation to throw a SAXParseException? Is it related to the schema or to the xml that I tried to parse?

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• mongodb : Can create new thread on FreeBSD?

  - by user197739

  We experienced some strange thing in our mongodb gridfs platform. The platform actually is a bi Xeon E5 (bi quad core) with 128GB of memory, running on freebsd 9 with a zfs pool dedicated for mongodb. [root@mongofile1 ~]# uname -sr FreeBSD 9.1-RELEASE our /boot/loader.conf vfs.zfs.arc_min="2048M" vfs.zfs.arc_max="7680M" vm.kmem_size_max="16G" vm.kmem_size="12G" vfs.zfs.prefetch_disable="1" kern.ipc.nmbclusters="32768" /etc/sysctl.conf net.inet.tcp.msl=15000 net.inet.tcp.keepidle=300000 kern.ipc.nmbclusters=32768 kern.ipc.maxsockbuf=2097152 kern.ipc.somaxconn=8192 kern.maxfiles=65536 kern.maxfilesperproc=32768 net.inet.tcp.delayed_ack=0 net.inet.tcp.sendspace=65535 net.inet.udp.recvspace=65535 net.inet.udp.maxdgram=57344 net.local.stream.recvspace=65535 net.local.stream.sendspace=65535 we follow the recommendation for the ulimit : [root@mongofile1 ~]# su - mongodb $ ulimit -a cpu time (seconds, -t) unlimited file size (512-blocks, -f) unlimited data seg size (kbytes, -d) 33554432 stack size (kbytes, -s) 524288 core file size (512-blocks, -c) unlimited max memory size (kbytes, -m) unlimited locked memory (kbytes, -l) unlimited max user processes (-u) 5547 open files (-n) 32768 virtual mem size (kbytes, -v) unlimited swap limit (kbytes, -w) unlimited sbsize (bytes, -b) unlimited pseudo-terminals (-p) unlimited This server have a twin (same config exactly) for ReplSet in other data center and we have a virtualized arbiter. Some time, almost 3 days, the process of mongodb exit. The problem begin with: Fri Nov 8 11:27:31.741 [conn774697] end connection 192.168.10.162:47963 (23 connections now open) Fri Nov 8 11:27:31.770 [initandlisten] can't create new thread, closing connection Fri Nov 8 11:27:31.771 [rsHealthPoll] replSet member mongofile2:27017 is now in state DOWN Fri Nov 8 11:27:31.774 [initandlisten] connection accepted from 192.168.10.162:47968 #774702 (20 connections now open) Fri Nov 8 11:27:31.774 [initandlisten] connection accepted from 192.168.10.161:28522 #774703 (21 connections now open) Fri Nov 8 11:27:31.774 [initandlisten] connection accepted from 192.168.10.164:15406 #774704 (22 connections now open) Fri Nov 8 11:27:31.774 [initandlisten] connection accepted from 192.168.10.163:25750 #774705 (23 connections now open) Fri Nov 8 11:27:31.810 [initandlisten] connection accepted from 192.168.10.182:20779 #774706 (24 connections now open) Fri Nov 8 11:27:31.855 [initandlisten] connection accepted from 192.168.10.161:28524 #774707 (25 connections now open) Fri Nov 8 11:27:31.869 [initandlisten] connection accepted from 192.168.10.182:20786 #774708 (26 connections now open) and after many "can create new thread" [root@mongofile1 /usr/mongodb]# tail -n 15000 mongod.log.old |grep "create new thread"|wc 5020 55220 421680 and finish by a magnificent Fri Nov 8 11:30:22.333 [rsMgr] replSet warning caught unexpected exception in electSelf() pure virtual method called Fri Nov 8 11:30:22.333 Got signal: 6 (Abort trap: 6). Fri Nov 8 11:30:22.337 Backtrace: 0x599efc 0x8035cb516 0x599efc <_ZN5mongo10abruptQuitEi+988> at /usr/local/bin/mongod 0x8035cb516 <_pthread_sigmask+918> at /lib/libthr.so.3 Extract of mongodb from top 78126 mongodb 77 20 0 1253G 1449M sbwait 0 0:20 0.00% mongod If I restart the process when it crash, the problem is fixed for almost 3 days. Has anyone seen this before, or know of a fix?

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• Seriousness of a "Smart" disk error. How long will it last?

  - by Workshop Alex

  I have an 1 TB data disk and the bios and Windows are reporting a "Smart" error. At least, I get a Smart event but it doesn't indicate how serious the failure could be. My system is about 6 months old, including the disk so the warranty will cover the damage. Unfortunately, I lack a second disk of 1 TB in size which I can use to make a full backup. The most important data on this disk is safe, but there's a lot of work data which can be regenerated but this would cost a lot of time. So I ordered an USB disk of 1 TB which will arrive in three days. By then I can make a full backup of the data and afterwards, it can crash. But will the disk live that long? (Well, I won't use the PC as long as I can't make a backup.) How serious is such a Smart event? I know it's serious enough to have it replaced, but will it live for another week or could it die any moment?Update: I purchased an 1 TB external disk and spent most of the day making a backup of the 1 TB disk. It survived that. I then received a new disk, since it was still under warranty and replaced the hard disk. Then I had to spend most of a day again to put back the backup. I need to send back the faulty disk and now have an additional external disk, which could always be practical. :-) The Smart Error report did not cause any failures on the original disk. I won't advise to ignore these warnings, but the disk still has enough life in it to last a few more days. (Just make sure you have a good back-up.) And oh, the horror of having to make a complete backup such a huge disk. :-) If your data is important, make sure you have something that supports incremental backups and lots of space. (In my case, the data wasn't very important, just practical to have on-disk together.)

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• Linux filesystem with inodes close on the disk

  - by pts

  I'd like to make the ls -laR /media/myfs on Linux as fast as possible. I'll have 1 million files on the filesystem, 2TB of total file size, and some directories containing as much as 10000 files. Which filesystem should I use and how should I configure it? As far as I understand, the reason why ls -laR is slow because it has to stat(2) each inode (i.e. 1 million stat(2)s), and since inodes are distributed randomly on the disk, each stat(2) needs one disk seek. Here are some solutions I had in mind, none of which I am satisfied with: Create the filesystem on an SSD, because the seek operations on SSDs are fast. This wouldn't work, because a 2TB SSD doesn't exist, or it's prohibitively expensive. Create a filesystem which spans on two block devices: an SSD and a disk; the disk contains file data, and the SSD contains all the metadata (including directory entries, inodes and POSIX extended attributes). Is there a filesystem which supports this? Would it survive a system crash (power outage)? Use find /media/myfs on ext2, ext3 or ext4, instead of ls -laR /media/myfs, because the former can the advantage of the d_type field (see in the getdents(2) man page), so it doesn't have to stat. Unfortunately, this doesn't meet my requirements, because I need all file sizes as well, which find /media/myfs doesn't print. Use a filesystem, such as VFAT, which stores inodes in the directory entries. I'd love this one, but VFAT is not reliable and flexible enough for me, and I don't know of any other filesystem which does that. Do you? Of course, storing inodes in the directory entries wouldn't work for files with a link count more than 1, but that's not a problem since I have only a few dozen such files in my use case. Adjust some settings in /proc or sysctl so that inodes are locked to system memory forever. This would not speed up the first ls -laR /media/myfs, but it would make all subsequent invocations amazingly fast. How can I do this? I don't like this idea, because it doesn't speed up the first invocation, which currently takes 30 minutes. Also I'd like to lock the POSIX extended attributes in memory as well. What do I have to do for that? Use a filesystem which has an online defragmentation tool, which can be instructed to relocate inodes to the the beginning of the block device. Once the relocation is done, I can run dd if=/dev/sdb of=/dev/null bs=1M count=256 to get the beginning of the block device fetched to the kernel in-memory cache without seeking, and then the stat(2) operations would be fast, because they read from the cache. Is there a way to lock those inodes and/or blocks into memory once they have been read? Which filesystem has such a defragmentation tool?

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